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Publications (10 of 59) Show all publications
Blasi Romero, A., Nguyen, H., Barbe, L., Tenje, M. & Mestres, G. (2019). Development and validation of a reusable microfluidic system for the evaluation of biomaterials’ biological properties. In: : . Paper presented at 2nd European Organ-on-Chip Conference (EUROoC 2019), 2-3 July 2019, Graz, Austria.
Open this publication in new window or tab >>Development and validation of a reusable microfluidic system for the evaluation of biomaterials’ biological properties
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2019 (English)Conference paper, Poster (with or without abstract) (Other academic)
Keywords
Biomaterials, biomaterials-on-chip, microfluidics
National Category
Medical Materials
Identifiers
urn:nbn:se:uu:diva-392966 (URN)
Conference
2nd European Organ-on-Chip Conference (EUROoC 2019), 2-3 July 2019, Graz, Austria
Available from: 2019-09-11 Created: 2019-09-11 Last updated: 2019-09-16Bibliographically approved
Trinh, M. N., Duy, N. V., Nguyen Duc, H., Chu, M. H., Nguyen, H. & Hieu, N. V. (2019). Effective design and fabrication of low-power-consumption self-heated SnO2 nanowire sensors for reducing gases. Sensors and actuators. B, Chemical, 295, 144-152
Open this publication in new window or tab >>Effective design and fabrication of low-power-consumption self-heated SnO2 nanowire sensors for reducing gases
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2019 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 295, p. 144-152Article in journal (Refereed) Published
Abstract [en]

Developing metal oxide gas sensors for internet-of-things (IoT) and portable applications require low-power consumption because of the limited battery in devices. This requirement is challenging because metal oxide sensors generally need high working temperatures, especially for reducing gases. Herein, we present an effective design and fabrication method of a SnO2 nanowire (NW) sensor for reducing gases by using the Joule heating effect at NW nanojunctions without needing an external or integrated heater. The sensor’s low-power consumption at around 4 mW was controlled by the size and nanojunction density of the device. The sensor has a simple design and is easy to fabricate. A proof-of-concept of a portable gas sensor module can be realised for monitoring highly toxic reducing gases, such as H 2S, NH3 and C2H5OH, by using the developed self-heated NWs.

Keywords
SnO2 nanowires; Nanojunction; Self-heated sensor; Low-power consumption.
National Category
Nano Technology Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-388489 (URN)10.1016/j.snb.2019.05.074 (DOI)000469849800018 ()
Available from: 2019-07-01 Created: 2019-07-01 Last updated: 2019-08-16Bibliographically approved
Carter, S.-S., Nguyen, H., Moreira, M., Tenje, M. & Mestres, G. (2019). Medical grade titanium on-chip: assessing the biological properties of biomaterials for bone regeneration. In: : . Paper presented at 2nd European Organ-on-Chip Conference, EUROoC 2019, Graz, Austria, July 2-3, 2019.
Open this publication in new window or tab >>Medical grade titanium on-chip: assessing the biological properties of biomaterials for bone regeneration
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2019 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Medical grade titanium on-chip: assessing the biological properties of biomaterials for bone regeneration

 

Sarah-Sophia D. Carter1, Hugo Nguyen2, Milena Moreira1, Maria Tenje1, and Gemma Mestres1

1Department of Engineering Sciences, Science for Life Laboratory, Uppsala University, Sweden

2Department of Engineering Sciences, Uppsala University, Sweden

 

Introduction

Before entering the clinic, biomaterials need to be thoroughly evaluated, which requires accurate in vitro models. In this work, we have developed a microfluidic device that could be used to assess the biological properties of biomaterials, in a more in vivo-like environment than what is currently possible.

 

Methods

Our device consists of a polydimethylsiloxane (PDMS, Sylgard 184) microfluidic channel (l= 6 mm, w= 2 mm, h= 200 µm) and a titanium disc (Ti6Al4V, at bottom), held together by an additively manufactured fixture (Fig. 1A). PDMS was cured overnight at 65°C on a silicon wafer master. Once the microchannel and titanium disc were positioned, MC3T3-E1 pre-osteoblast-like cells were seeded (50,000 cells/cm2). After 5 hours incubation under standard culture conditions, flow was started (2 μl/min). As a control, MC3T3-E1 cells were seeded onto plain titanium discs off-chip. Cell viability and morphology were assessed after 20 hours by calcein-AM/propidium iodide (PI), staining live and dead cells respectively.

 

Results and discussion

Figure 1B and 1C show calcein-AM/PI stained MC3T3-E1 cells cultured on-chip and figure 1D shows the control, MC3T3-E1 cells cultured off-chip. The potential to culture cells in our chip was confirmed by the presence of a majority of viable cells (green) with a similar morphology as the control sample. The reason for the increased amount of dead cells (red) on-chip compared to the control needs to be further examined, which requires longer-term experiments.

Conclusion

We have set the first steps towards a microfluidic tool for the assessment of biological properties of biomaterials.

Keywords
Organ-on-chip, biomaterials, microfluidics
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Microsystems Technology
Identifiers
urn:nbn:se:uu:diva-393277 (URN)
Conference
2nd European Organ-on-Chip Conference, EUROoC 2019, Graz, Austria, July 2-3, 2019
Funder
Knut and Alice Wallenberg Foundation, WAF 2016-0112Vattenfall AB, 2017-05051
Available from: 2019-09-18 Created: 2019-09-18 Last updated: 2019-09-20Bibliographically approved
Duoc, V. T., Le, D. T., Hoa, N. D., Duy, N. V., Hung, C. M., Nguyen, H. & Hieu, N. V. (2019). New Design of ZnO Nanorod- and Nanowire-Based NO2 Room-Temperature Sensors Prepared by Hydrothermal Method. Journal of Nanomaterials, Article ID 6821937.
Open this publication in new window or tab >>New Design of ZnO Nanorod- and Nanowire-Based NO2 Room-Temperature Sensors Prepared by Hydrothermal Method
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2019 (English)In: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, article id 6821937Article in journal (Refereed) Published
Abstract [en]

Room-temperature gas sensors are attracting attention because of their low power consumption, safe operation, and long-term stability. Herein, ZnO nanorods (NRs) and nanowires (NWs) were on-chip grown via a facile hydrothermal method and used for room-temperature NO2 gas sensor applications. The ZnO NRs were obtained by a one-step hydrothermal process, whereas the NWs were obtained by a two-step hydrothermal process. To obtain ZnO NW sensor, the length of NRs was controlled short enough so that none of the nanorod-nanorod junction was made. Thereafter, the NWs were grown from the tips of no-contact NRs to form nanowire-nanowire junctions. The gas-sensing characteristics of ZnO NRs and NWs were tested against NO2 gas at room temperature for comparison. The gas-sensing characteristics of the sensors were also tested at different applied voltages to evaluate the effect of the self-activated gas-sensing performance. Results show that the diameter of ZnO NRs and NWs is the dominant parameter of their NO2 gas-sensing performance at room temperature. In addition, self-activation by local heating occurred for both sensors, but because the NWs were smaller and sparser than the NRs, local heating thus required a lower applied voltage with maximal response compared with the NRs.

Place, publisher, year, edition, pages
HINDAWI LTD, 2019
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-383211 (URN)10.1155/2019/6821937 (DOI)000465300600001 ()
Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-05-10Bibliographically approved
Nguyen, T. Q., Phan, D. T., Nguyen, D. D., Nguyen, H. & Tran, S. T. (2019). Numerical study of a wide incident angle- and polarisation-insensitive microwave metamaterial absorber based on a symmetric flower structure. AIP Advances, 9(6), Article ID 065318.
Open this publication in new window or tab >>Numerical study of a wide incident angle- and polarisation-insensitive microwave metamaterial absorber based on a symmetric flower structure
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2019 (English)In: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 9, no 6, article id 065318Article in journal (Refereed) Published
Abstract [en]

In this study, we propose a wide incident angle- and polarisation-insensitive metamaterial absorber covered with structures comprising a metallic flower shape layer, a dielectric layer and a metallic ground plane. The influences of the structural parameters on the absorptivity are investigated numerically. The proposed absorber exhibits polarisation insensitivity as the number of symmetric petals of a flower shape reaches as high as 4, 6 and 8. Particularly, the absorber based on 8 petals shows an absorptivity of above 90% for wide incident angles up to 70° under transverse electric and transverse magnetic polarisations. The physical mechanism of these observations is clarified by investigating the electric, power loss density and induced current distributions, which is also supported by the retrieved constitutive electromagnetic parameters. That is, the absorption phenomenon is considerably affected by magnetic resonance. By modifying the petals into hollow shapes, the absorber becomes effective in confining the magnetic resonance and can thus minimise the resonant frequency variation to 0.22% without affecting the absorption performance. In comparison with other reported metamaterial absorbers, our design shows considerable practical feasibility in terms of resonant frequency stability, wide incident angle and polarisation insensitivity, thereby making it suitable for various applications in microwave frequency region.

National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-387695 (URN)10.1063/1.5098005 (DOI)000474430700034 ()
Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2019-09-11Bibliographically approved
Hoa, N. T., Lam, P. H., Tung, P. D., Tuan, T. S. & Nguyen, H. (2019). Numerical Study of a Wide-Angle and Polarization-Insensitive Ultrabroadband Metamaterial Absorber in Visible and Near-Infrared Region. IEEE Photonics Journal, 11(1), Article ID 4600208.
Open this publication in new window or tab >>Numerical Study of a Wide-Angle and Polarization-Insensitive Ultrabroadband Metamaterial Absorber in Visible and Near-Infrared Region
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2019 (English)In: IEEE Photonics Journal, ISSN 1097-5764, E-ISSN 1943-0655, Vol. 11, no 1, article id 4600208Article in journal (Refereed) Published
Abstract [en]

An ultrabroadband metamaterial absorber structure based on a periodic array of metallic-dielectric multilayered conical frustums is numerically investigated and proposed. The metamaterial absorber indicated an absorptivity of higher than 90%, which covered the visible and near-infrared region at 480-1480 nm, and a relative absorption bandwidth of 102%. The high absorptivity can be maintained with large incident angles up to 60 degrees under both transverse electric and transverse magnetic polarizations. Furthermore, the proposed absorber exhibits polarization insensitivity owing to its rotational symmetry structure. Compared with the previously reported ultrabroadband metamaterial absorbers, the design in this work indicates high practical feasibility in terms of a compact structure for a large bandwidth, a wide incident angle, and polarization insensitivity, thereby suggesting its promising application, for example, in solar cells and thermal emitters.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Absorber, metamaterial, near-infrared, ultrabroadband, visible
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-376809 (URN)10.1109/JPHOT.2018.2888971 (DOI)000456325300001 ()
Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2019-02-22Bibliographically approved
Trinh, M. N., Nguyen, V. D., Chu, M. H., Nguyen, D. H., Nguyen, H., Tonezzer, M. & Nguyen, V. H. (2019). Self-heated Ag-decorated SnO2 nanowires with low power consumption used as a predictive virtual multisensor for H2S-selective sensing. Analytica Chimica Acta, 1069, 108-116
Open this publication in new window or tab >>Self-heated Ag-decorated SnO2 nanowires with low power consumption used as a predictive virtual multisensor for H2S-selective sensing
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2019 (English)In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 1069, p. 108-116Article in journal (Refereed) Published
Abstract [en]

Multisensor systems with low-power consumption are emerging for the Internet of Things. In this work, we demonstrate the use of self-heated networked Ag-decorated SnO2 NW sensors integrated into a portable module for selective detection of H2S gas at low power consumption, and the integrated system is simulated as a virtual multisensor under varying heating powers for identifying and quantifying different reducing gases. The H2S gas-sensing characterisations at the different self-heating powers of 2–10 mW showed that the gas response significantly increased with the increase in Ag density decoration and the heated power strongly affected the gas-sensing performance and sensor stability. Excellent response of 21.2 to 0.5 ppm H2S gas was obtained at a low heating power of 2 mW with an acceptable response/recovery time of 18/980 s. The increase of the heating power over 20 mW can destroy the devices. The integrated system could selectively detect H2S at the heating power below 4 mW and H2, C2H5OH and NH3gases at the heating power upon 4 mW. The virtual multisensor could discriminate qualitatively (with an accuracy of 100%) and quantitatively H2S, H2, NH3, C2H5OH (Ethanol) and CH3COCH3 (Aceton) gases with average errors of 13.5%, 14.7%, 16.8%, 16.9%, and 14.8%, respectively. The proposed sensing platform is a promising candidate for selective detection of H2S gas and virtual multisensor with low power consumption for mobile or wireless network devices.

Keywords
Self-heated sensor, H2S gas, Nanojunctions, Networked nanowires
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-383238 (URN)10.1016/j.aca.2019.04.020 (DOI)000467535900011 ()31084736 (PubMedID)
Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-06-20Bibliographically approved
Jiao, M., Nguyen, v. D., Nguyen, V. C., Nguyen, D. H., Nguyen, V. H., Hjort, K. & Nguyen, H. (2018). Comparison of NO2 Gas-Sensing Properties of Three Different ZnO Nanostructures Synthesized by On-Chip Low-Temperature Hydrothermal Growth. Journal of Electronic Materials, 47(1), 785-793
Open this publication in new window or tab >>Comparison of NO2 Gas-Sensing Properties of Three Different ZnO Nanostructures Synthesized by On-Chip Low-Temperature Hydrothermal Growth
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2018 (English)In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 47, no 1, p. 785-793Article in journal (Refereed) Published
Abstract [en]

Three different ZnO nanostructures, dense nanorods, dense nanowires, and sparse nanowires, were synthesized between Pt electrodes by on-chip hydrothermal growth at 90°C and below. The three nanostructures were characterized by scanning electron microscopy and x-ray diffraction to identify their morphologies and crystal structures. The three ZnO nanostructures were confirmed to have the same crystal type, but their dimensions and densities differed. The NO2 gas-sensing performance of the three ZnO nanostructures was investigated at different operation temperatures. ZnO nanorods had the lowest response to NO2 along with the longest response/recovery time, whereas sparse ZnO nanowires had the highest response to NO2 and the shortest response/recovery time. Sparse ZnO nanowires also performed best at 300°C and still work well and fast at 200°C. The current–voltage curves of the three ZnO nanostructures were obtained at various temperatures, and the results clearly showed that sparse ZnO nanowires did not have the linear characteristics of the others. Analysis of this phenomenon in connection with the highly sensitive behavior of sparse ZnO nanowires is also presented.

National Category
Other Materials Engineering
Identifiers
urn:nbn:se:uu:diva-320153 (URN)10.1007/s11664-017-5829-6 (DOI)000418580800093 ()
Available from: 2017-04-16 Created: 2017-04-16 Last updated: 2018-01-29Bibliographically approved
Sahlberg, A., Nilsson, F., Berglund, A., Nguyen, H., Hjort, K. & Jeong, S. H. (2018). High-Resolution Liquid Alloy Patterning for Small Stretchable Strain Sensor Arrays. Advanced materials technologologies, 3(4), Article ID 1700330.
Open this publication in new window or tab >>High-Resolution Liquid Alloy Patterning for Small Stretchable Strain Sensor Arrays
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2018 (English)In: Advanced materials technologologies, ISSN 2365-709X, Vol. 3, no 4, article id 1700330Article in journal (Refereed) Published
Abstract [en]

Soft material applied technology has in recent years become more advanced, enabling for, e.g., soft robotics, skin electronics, and wearable systems. Yet, the processing technology of soft materials has not been sufficiently developed to create high performance in soft and stretchable systems, as compared to the processing technology of conventional electronics or electromechanical systems. Liquid alloys have shown excellent properties for soft and stretchable electrical interconnectors and conductors, which is a basic building block to produce electric or electromechanical systems. In order to overcome the limited resolution of previously developed liquid alloy patterning methods for large-area printed circuits, this work explores the possibility of employing shrinking substrates. By utilizing the characteristics of liquid alloys and elastomers the pattern resolution is improved through a stretch-shrink patterning (SSP) process. The process provides highly conductive liquid conductors of high resolution and can be combined with existing printing techniques for liquid alloys. The SSP process increases design flexibility of soft and stretchable systems that use liquid alloys and enables designs with finer and denser patterns, and cost-effective production for small scale systems.

Keywords
elastomers, high-resolution patterning, liquid alloys, shrink substrates, stretchable strain sensors
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:uu:diva-353211 (URN)10.1002/admt.201700330 (DOI)000430164100012 ()
Available from: 2018-06-13 Created: 2018-06-13 Last updated: 2018-06-14Bibliographically approved
Jiao, M., Nguyen Viet, C., Duy, N. V., Nguyen Duc, H., Hieu, N. V., Hjort, K. & Nguyen, H. (2018). Influence of annealing temperature on theperformance and stability of on-chip hydrothermally grown ZnO nanorod gassensor toward NO2. Academia Journal of Scientific Research, 6(5), 180-189
Open this publication in new window or tab >>Influence of annealing temperature on theperformance and stability of on-chip hydrothermally grown ZnO nanorod gassensor toward NO2
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2018 (English)In: Academia Journal of Scientific Research, ISSN 2315-7712, Vol. 6, no 5, p. 180-189Article in journal (Refereed) Published
Abstract [en]

Nanorod-based gas sensors synthesized at low temperature should generally be stabilized by anneling before usage. However, the influence of annealing on the sensing performance and stability of these nanorods is rarely reported. In this study, we first fabricated gas sensors based on ZnO nanorods grown on-chip on glass substrate using hydrothermal method. Subsequently, these sensors were annealed at either 400 °C, 500 °C, or 600 °C in air for 4 h. The gas-sensing performance of the ZnO nanorods toward NO2 was tested before and after annealing. The sensitivity of the gas sensors to NO2 decreased, but the stability increased with the increase in annealing temperature. Photoluminescence spectroscopy and X-ray diffraction were used to investigate the material structure of ZnO nanorods. Results revealed that the oxygen-atom-related defects in the ZnO lattice in the region close to the surface influenced by annealing process were the most significant factors on the sensing properties and stability of ZnO nanorods.

Keywords
Annealing, defects in nanorods, gas sensor, hydrothermal, zinc oxide.
National Category
Other Natural Sciences Engineering and Technology
Research subject
Engineering Science with specialization in Microsystems Technology
Identifiers
urn:nbn:se:uu:diva-363650 (URN)10.15413/ajsr.2018.0104 (DOI)
Available from: 2018-10-18 Created: 2018-10-18 Last updated: 2018-10-19Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8055-5820

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